Two-stage arming mechanism

ABSTRACT

A two-stage arming mechanism for a spin-to-arm munition. This arming mechanism contains two arming means therein which must be activated in sequence in order to fully arm the mechanism. The first means is actuated by spin velocity, while the second means is activated by angular deceleration which occurs during ground impact. Unless both conditions are met in the proper sequence the arming mechanism will not fully arm.

United States Patent 1 Lindberg [4511 m 31, 1973 4] TWO-STAGE ARMING MECHANISM 1,614,537 1/1927 Pantoflicek 102/79 3,397,641 8/1968 Gerick 102/79 [751 Ihvehm M'hhemhka 3,450,049 6/1969 Dare 102/80 [73] Assignee: The United States of America as Primary Examiner$amuel W. Engle represented by the Secretary of the Att0meyHarry A. Herbert, Jr. et a]. Air Force, Washington, DC.

[22] Filed: Oct. 14, 1971 [57] ABSTRACT 1 1 pp 189,284 A two-stage arming mechanism for a spin-to-arm munition. This arming mechanism contains two arming 52 U.S. Cl 102/79 102/76 P means therein which be activated in Sequeh 51 1m. (:1. r 426 15/22 the mechanism The first means is [58] Field at Search 162/76 78 79 so hated by "emhy, while means is vated by angular deceleration which occurs during [56] References and ground impact. Unless both conditions are met in the proper sequence the arming mechanism will not fully UNITED STATES PATENTS arm 1,618,944 2/1927 Pantoflicek... 3,326,131 6/1967 Hazelet 102/79 6 Claims, 6 Drawing Figures PATENTEDJUL31 I915 3'. 749.022

SHEET 2 0F 2 INVFNTOR. (l/4P4 3 LINDBERG BY w BACKGROUND OF THE INVENTION This invention relates generally to arming mechanisms and, more particularly, to an arming mechanism which utilizes two independent arming signals for activation.

In many types of bombs or mines which are to be activated upon spinning, it is desirable for the arming mechanism to activate the bomb or any other such device associated therewith after a short delay. This delay is an important feature of such an arming mechanism since it is essential that the bomb or device not function until after it has been released. In this manner the bomb can be delivered outside the radius of danger of the delivering means. Furthermore, this provides some degree of safety in the case of falling bombs which strike each other or in the case where the bombs are released while the plane or other delivering means is on the ground or at a low altitude, or in the case where the bomb has been released inadvertently.

In the normal functioning operation of a spin-toarm munition, the bomb is released from a delivering means and spins up due to aerodynamic forces during freefall. It is essential that the bomb is not activated until it comes in contact with the ground. Heretofore, complex mechanisms were required in order to prevent the unacceptable arming of such a spin-to-arm munition. The complexity of these arming mechanisms made for an increased number of failures during operation. Furthermore, the increased complexity greatly increased the cost of manufacture.

SUMMARY OF THE INVENTION The instant invention sets forth an arming mechanism which overcomes the problems set forth hereinabove.

The spin velocity/deceleration arming mechanism of this invention is designed to satisfy the requirements for dual environment arming in spinning munitions. In other words, the device of this invention contains two series arming mechanisms which utilize independent arming signals, namely the device spin-up to a minimum velocity and ground impact for device deceleration. The present arming mechanism does not utilize any stored energy mechanism for its operation.

During normal operation when sufficient rotating velocity is reached by the arming mechanism of this invention a plurality of spin weights move laterally outward and allow a rotor release to move into a rotor assembly. This rotor assembly is made up of a rotor housing, a plurality of spin weights and springs associated therewith, the rotor release and its spring, and an interruptor plate. When the rotor release is moved into the rotor assembly, the rotor assembly is free to rotate approximately 30" when the angular deceleration caused by ground impact is sufficient to overcome a detent spring force. The angular momentun of the rotor assembly causes the interruptor plate to rotate into the fully armed position. If the bomb or munition operably associated with the arming mechanism of this invention does not experience both spin velocity and angular deceleration of sufficient magnitude and in the normal sequence, it will not arm.

For example, if a high angular acceleration occurs before sufficient spin velocity has been achieved, the arming mechanism will partially arm in a safe condition and remain safe and inoperable. This feature of the instant invention makes the device safe during and after an accidental drop in the factory or during accidental release or jettison of a dispenser from an aircraft. If spin-up is to occur under these conditions it will occur suddenly and the high angular acceleration will cause the rotor assembly to rotate before the rotor release has moved into the rotor assembly. Sufficient rotation under these conditions cannot take place and therefore is insufficient to fully arm the mechanism.

It is therefore an object of this invention to provide an arming mechanism which relies upon a pair of independent arming signals for operation thereof.

It is another object of this invention to provide an arming mechanism which is completely safe and inoperable until all arming signals have been met in predetermined sequence.

It is another object of this invention to provide an arming mechanism which is economical to produce, highly reliable in operation, and which utilizes conventional, currently available components that lend themselves to standard manufacturing producing techniques.

For a better understanding of the present invention together with other and further objects thereof, reference is made to the following description taken in connection with the accompanying drawing and its scope will be pointed out in the appended claims.

DESCRIPTION OF THE- DRAWING Fig. l is a side elevational view, shown partly in cross-section, of the arming mechanism of this invention in its unarmed position;

FIG. 2 is a plan view taken along lines 2--2 of FIG. I and shown partly in cross-section;

FIG. 3 is a plan view talren along lines 3-3 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Reference is now made to FIGS. 1-3 of the drawing which shows the arming mechanism 10 of this invention in the unarmed position.

Arming mechanism ill) is made up of an outer hous ing 12 which may form part of any suitable munition (not shown) and contain any conventional detonator 14. Also within outer housing 12 is a rotor assembly 16. Rotor assembly 116 is rotatably mounted within housing 12 and is made up of a rotor housing 1%, a plurality of spin weights 20 slideably secured within housing 118, a rotor release 22 having a pair of legs 23 and an interrupter plate 24 through which said legs 23 protrude. A base plate 26 (FIGS. ii and 3) is positioned within outer housing 12 adjacent interrupter plate. This base plate 26 has an aperture 25 therein which exposes detonator 14 when the arming mechanism M) is in the fully armed position. Holding all these elements in place is any suitable cover 28 fixedly secured at its ends to housing 12.

The rotor housing 18 is prevented from accidental rotation by any suitable biasing means such as detent spring 30 fixedly secured at one end to outer housing 12 and having the other end of spring 30 resting in detent 34 of rotor housing 18. Spring 30 is of sufficient strength to prevent rotation of housing 18 except during a sudden angular deceleration of mechanism as produced upon impact with the ground, for example. Slideably mounted within rotor housing 18 are a plurality of spin weights 20 biased to the inner position, as shown in FIG. 1, by a spring 36 associated with each weight 20. These springs 36 are of sufficient strength to prevent movement of weights 20 except during apredetermined rotational velocity of mechanism 10, as for example, during spin-up of the munition during freefall.

Located adjacent weights 20 and held in the extended position by outstanding portions 38 of weights 20, as shown in FIG. 1, is a rotor release 22. Rotor release 22 is biased against the outstanding portions 38 of weights 20 by spring 40. In the unarmed position as shown in FIGS. 1-3 the legs 23 of rotor release 22 extend through an opening 44 in interrupter plate 24 (best shown FIG. 2) and an opening 46 in base plate 26 (FIG. 3). Also secured to housing 12 is any suitable locking means such as rotor lock springs 48 which are utilized to engage serrated edge 50 of interrupter plate 24 and lock the interrupter plate 24 in either the fully armed or safe position in a manner to be explained in detail hereinbelow.

The rotor assembly 16 can arm or lock safe in either direction while detent spring 30 prevents rotation of the rotor assembly during the relatively low angular acceleration which occurs during free-fall of the munition. Further, the rotor assembly 16 must be balanced about its axis of rotation by any conventional arrangement which does not constitute part of the instant invention.

MODE OF OPERATION Reference is now made to FIGS. 1-6 which show the various positions of operation of arming mechanism 10 of this invention. a

In the unarmed position as shown in FIGS. 1-4 arming weights 20 are biased by springs 36 to the innermost position (FIG. 1). In this position outstanding portions 38 of weights 20 hold rotor release 22 in the position wherein legs 23 thereof extend through opening 44 in interrupter plate 24 and openings 46 in base plate 26. Also in the unarmed position detent spring 30 prevents accidental rotation of rotor assembly 16.

When sufficient rotational velocity takes place, as in the case when the munition is released from a conventional delivery means such as an aircraft, the spin weights 20 move radially outward against the action of springs 36 as shown in FIG. 4 of the drawing. Upon the movement of the spin weights 20 into the position shown in FIG. 4, the rotor release 22 is forced into the rotor assembly 16 by spring 40. With the rotor release 22 moved into the rotor assembly 16 as shown in FIG. 4, the legs 23 thereof no longer protrude through the base plate 26. The rotor assembly 16 of arming mechanism 10 can now rotate approximately 30 to the position shown in FIG. 5 when an angular deceleration takes place which is sufficient to overcome the force of detent spring 30. Such an angular deceleration takes place when the munition strikes any substantial object such as the ground. The angular momentum of rotor assembly 16 causes it to rotate the interrupter plate 24 from the position shown in FIG. 2 to the position shown in FIG. 5 whereby the detonator 14 is now fully exposed. As the arming mechanism 10 of the instant invention reaches the fully anned position shown in FIGS. 4 and 5, the serrated edge 50 of interrupter plate 24 engages either of rotor lock springs 48 and the interrupter plate 24 is thereby prevented from returning to the unarmed position. In the armed position the detonator 14 is exposed through aperture 25 in base plate 26 and is capable of being activated by any conventional activation means.

Ifthe munition, however, fails to experience both the spin velocity and angular deceleration of sufficient magnitude and in the normal sequence, the arming mechanism 10 of this invention will not fully armbut will reach a partially armed or safe position as described hereinbelow with respect to FIG. 6 of the drawing. If spin-up of the munition is to occur suddenly, that is, contrary to the gradual spin-up produced during normal free-fall, the high angular acceleration will cause rotor assembly 16 to overcome the force of detent spring 30 and rotate before the spin weights 20 have moved outwardly. In this case the rotor release 22 has not moved into the rotor assembly 16 but remains in the position shown in FIG. 1 with legs 23 protruding through opening 44 in interrupter plate 24 and openings 46 in base plate 26. It therefore becomes possible to rotate the rotor assembly 16 only approximately 15, that is, until the protruding feet of legs 23 of rotor release 22 hook under base plate 26, as shown in FIG. 6. In this position the 15 rotation of interrupter plate 24 is insufficient to expose detonator 14 but is sufficient for the serrated edge 50 of interrupter plate 24 to engage rotor lock spring 48. The arming mechanism 10 is thereby locked in the partially armed or safe position.

The instant invention therefore produces an arming mechanism 10 which relies upon two independent arming signals for activation thereof. Without both these signals in a predetermined sequence the arming mechanism 10 will remain in a safe position without the possibility of being accidentally activated.

Although the invention has been described with reference to a particular embodiment, it will be understood to those skilled in the art that this invention is also capable of a variety of alternate embodiments within the spirit and scope of the appended claims.

I claim:

1. A two-stage arming mechanism comprising an outer housing, a detonator located within said housing, a rotor assembly rotatably mounted within said outer housing adjacent said detonator, a plurality of spin weights slideably mounted within said rotor assembly, a rotor release slideably mounted adjacent said spin weights, means for biasing said spin weights against said rotor release preventing said rotor release from moving into said rotor assembly and thereby allowing said rotor assembly from rotating to the fully armed position until predetermined rotational velocity has been reached, and a spring having one end thereof secured to said outer housing and the other end only resting against said rotor assembly for preventing the rotation of said rotor assembly until a predetermined angular deceleration has been reached, whereby upon suflicient rotational velocity and sufficient angular deceleration of said arming mechanism said rotor assembly rotates to the fully armed position thereby exposing said detonator for activation thereof.

2. A two-stage arming mechanism as defined in claim ll further comprising an interrupter plate rotatably mounted within said outer housing adjacent said rotor release and overlying said detonator when said arming mechanism is in the unarmed or safe position, said interrupter plate having an opening therein through which a portion of said rotor release extends, and a base plate mounted within said outer housing adjacent said interrutper plate, said base plate having at least one opening therein through which said portion of said rotor release extends when said arming mechanism is in the unarmed position.

3. A two-stage arming mechanism as defined in claim 2 wherein locking means are mounted on said outer housing for engaging said interrupter plate when said lying said detonator thereby exposing said detonator when said arming mechanism is in the fully armed position. 

1. A two-stage arming mechanism comprising an outer housing, a detonator located within said housing, a rotor assembly rotatably mounted within said outer housing adjacent said detonator, a plurality of spin weights slideably mounted within said rotor assembly, a rotor release slideably mounted adjacent said spin weights, means for biasing said spin weights against said rotor release preventing said rotor release from moving into said rotor assembly and thereby allowing said rotor assembly from rotating to the fully armed position until predetermined rotational velocity has been reached, and a spring having one end thereof secured to said outer housing and the other end only resting against said rotor assembly for preventing the rotation of said rotor assembly until a predetermined angular deceleration has been reached, whereby upon sufficient rotational velocity and sufficient angular deceleration of said arming mechanism said rotor assembly rotates to the fully armed position thereby exposing said detonator for activation thereof.
 2. A two-stage arming mechanism as defined in claim 1 further comprising an interrupter plate rotatably mounted within said outer housing adjacent said rotor release and overlying said detonator when said arming mechanism is in the unarmed or safe position, said interrupter plate having an opening therein through which a portion of said rotor release extends, and a base plate mounted within said outer housing adjacent said interrutper plate, said base plate having at least one opening therein through which said portion of said rotor release extends when said arming mechanism is in the unarmed position.
 3. A two-stage arming mechanism as defined in claim 2 wherein locking means are mounted on said outer housing for engaging said interrupter plate when said arming mechanism is in the fully armed or safe position.
 4. A two-stage arming mechanism as defined in claim 2 wherein said interrupter plate has a serrated edge thereon for engaging said locking means.
 5. A two-stage arming mechanism as defined in claim 4 wherein said means for biasing said spin weights are springs.
 6. A two-stage arming mechanism as defined in claim 5 wherein said base plate has an aperture therein overlying said detonator thereby exposing said detonator when said arming mechanism is in the fully armed position. 